This invention relates generally to manual transmission shifters and, more particularly, to a manual transmission shifter which operates two control cables that move independently of each other.
Shifters for operating manual transmissions have been in existence for decades. These shifters have taken many forms and have been located in many different positions on a vehicle. Some shifters are mounted directly atop the transmission and control the transmissions by directly moving levers.
Other shifters have been mounted on the vehicle's steering column remote from the transmission and operate the transmission by a series of articulated linkages. Currently, most shifters are floor-mounted at a location remote from the transmission. Recently, vehicles have become smaller, more compact and burdened with under-floor pollution control equipment. This has complicated the use of articulated linkages, because there is no longer an uncluttered straight path between the shifter and the transmission.
Accordingly, so-called "cable shifters" have been developed. These shifters manipulate two Bowden, or push-pull, cables to operate the transmission. An early example of a cable shifter of this type is shown in U.S. Pat. No. 4,143,560 to Kinkade et al. which features a ball shifter which operates a pair of transmission control cables by moving a shift lever about intersecting orthogonal shift lever axes. One of the control cables is operated directly by a lower extension of the shift lever when the lever is moved about one of the shift lever axes. The other cable is indirectly operated by a bellcrank which is pivoted by movement of the shift lever about the other shift lever axis.
One problem encountered with this type of shifter is lateral flexing movement of the directly-operated cable when the other cable is operated by the shift lever. In an attempt to overcome this problem, a depending pivoted link was interposed between the shift lever and the directly-operated control cable. This arrangement is disclosed in U.S. Pat. No. 4,693,135 to LaRocca et al. which features a similar ball shifter which operates two transmission control cables by moving a shift lever about intersecting orthogonal axes. This arrangement reduces the unwanted lateral flexing movement of the cable. However, this movement is not eliminated and the added pivot point introduces a point of potential looseness, or "play" in the linkage.
It would be desirable to provide a shifter which controls two transmission control cables by moving the shift lever about orthogonal axes to operate one cable without moving the non-operated cable.
It would also be desirable to provide such a shifter which eliminates "play" in the cable control linkage.